Packet data networks, their structure, and their operation are generally known. Examples of packet data networks include Local Area Networks (LANs), Wide Area Networks (WANs), and the Internet, among others. Packet data networks may be wired, wireless, or a combination of wired and wireless networks. Particular examples of networks include wired Ethernet LANs (IEEE 802.3 networks), wireless LANs (IEEE 802.11 networks), and Home Networks (HomePNA networks), among others. Each of these networks services data communications between groups of intercoupled network clients. As network client data exchange demands have increased, operating capabilities of these networks have also increased. For example, wired Ethernet LANs first serviced data communications at relatively low data throughput rates, e.g., 10 MBPS but now service data communications at relatively higher data rates, e.g., 100 MBPS, 1 GBPS, and higher. HomePNA networks have also evolved to support greater data rates with each HomePNA Specification revision.
The HomePNA Specification sets forth operations that, when implemented, allow a plurality of network devices to communicate with one another via premises telephone wiring, e.g., unshielded twisted pair (UTP) wiring. A currently existing version of the HomePNA Specification is known as the HomePNA 2.0 Specification. The HomePNA 2.0 Specification specifies a frequency band of 4-10 MHz, a carrier frequency of 7 MHz, preamble/header/trailer symbol rates of 2 MBaud, payload symbol rates of 2 and 4 MBaud, and constellations of between 2 and 8 bits/symbol. In a typical HomePNA network installation, a plurality of network devices, e.g., computers, share the premises telephone wiring with telephones and other devices that access the telephone network via the telephone wiring.
With HomePNA networks as well as other networks, each network device is usually compliant with one particular version of a corresponding operating standard, e.g., the HomePNA 2.0 Specification. In most installations, it is desirable for devices that support differing versions of the operating standard to share a common physical media. For example, in a HomePNA network, it is desirable for some network devices that support an old version of the HomePNA Specification to share the UTP wiring with other network devices that support a new version of the HomePNA Specification. However, inherent incompatibility typically exists between network devices supporting old versions of the standard as compared to network devices supporting new versions of the standard. With some operating standards, such as the HomePNA Specification, newer versions require operation in a wider frequency band. To maintain compatibility with existing standards and legacy devices, however, the total transmit power level should remain the same between old version legacy devices and new version devices. One approach for maintaining the same power level for a new version signal with a greater frequency range is to reduce the power spectral density of the signal. With this approach, however, old version systems may not sense a transmission from a new version device that is intended for it. Thus, when a corresponding network is upgraded, all network devices are typically modified so that they all support the new version of the standard. In this fashion, all network devices will support the higher data rates of the new version. Unfortunately, upgrading from an old version of the standard to a new version of the standard requires the purchase of additional hardware and/or software that may be significantly expensive.
Thus, there is a need in the art for devices that support a new version of an operating standard but that are backwards compatible with devices that support old versions of the operating standard. With this backwards compatibility operation, the higher rates of the new version of the standard must also be supported between new version devices. Further, these devices must embody a methodology that simplifies bandwidth compatibility between old version devices and new version devices.